There is great deal of interest at the present time in defining inappropriate temperatures to which products like foods and pharmaceuticals have been exposed. This information can then be used to reject the products and hence protect consumer health. Similarly, it is important that a time delay or shelf-life is built into a quality monitoring system. The following text defines the development of a novel time-temperature indicator which can trigger one or more detection systems.
Until recently, time-temperature indicators have been based around the production of easily visible responses to time-temperature linked events. However, limitations are imposed upon these systems in the sense that every product must be examined by eye or another optical system to confirm that a chemical event had occurred. The following invention is applicable to optical systems in a broad sense in terms of the activation and compartmentalisation technologies employed.